Other Mingus albums such as Pithecanthropus Erectus, Mingus Ah Um and Mingus Mingus Mingus Mingus Mingus will probably suit you well. John Coltrane's Ascension is a must, as is Ornette Coleman's The Shape Of Jazz To Come and Free Jazz. Also check out Eric Dolphy, his albums Out To Lunch and Out There are both amazing, and out there features Ron Carter on cello. Andrew Hill is also a must, check out Point Of Departure, it features Joe Henderson, Kenny Dorham and Dolphy at their abstract best. Let me know if you've got all that already, I could suggest more.

The Black Saint... but if you want some primal jazz, maybe try some Peter Brotzmann (Machine Gun). If you want it a bit more reigned in, but still intense, try Evan Parker's "Time Lapse". I always recommend Don Cherry's Eternal Rhythm and Brown Rice in these kinds of threads too. If nothing else, try and get your hands on the track "Malkauns" from the latter album. Eastern drone with the most amazing trumpet solo you've ever heard. Its not really dark, but it takes you into outer space.